Three-dimensional display module using optical wave-guide for providing directional backlights

Patent metadata

Field	Value
Publication number	US-11480796-B2
Application number	US-202117149765-A
Country	US
Kind code	B2
Filing date	Jan 15, 2021
Priority date	Jan 16, 2020
Publication date	Oct 25, 2022
Grant date	Oct 25, 2022

Abstract

The invention discloses a three-dimensional display module using optical wave-guide for providing directional backlights. This display module includes a wave-guide backlight unit with time-sequential directional light sources, a display device, a wavefront modulation device or a light splitting device, and other components. The wave-guide backlight unit with time-sequential directional light sources includes a sequential-switching light-source array, a relay device, and an optical wave-guide device. Each light source of the sequential-switching light-source array provides backlight of corresponding vector characteristics to the display device, making optical message displayed by the display device being guided to the corresponding viewing zone/viewing zones. Through the technology routes of multiple-view-for-one-pupil or/and Maxwellian view, the three-dimensional display module implements displays free from the vergence-accommodation conflict. The introduction of the optical wave-guide device results in a thin structure, and the disclosed display module can be applied to various display terminals, such as mobile phones, iPads, head-mounted VR/AR, etc.

First claim

What is claimed is:

1. A three-dimensional display module using optical wave-guide for providing directional backlights, comprising:
a wave-guide backlight unit with time-sequential directional light sources, which comprises a sequential-switching light-source array composed of M light sources, a relay device for modulating a light from each light source, and an optical wave-guide device for guiding lights from the relay device, where M≥2, wherein the wave-guide backlight unit with time-sequential directional light sources is arranged such that the M light sources get turned-on sequentially at the M time-points of each time period, and the light emitted from each light source provides a backlight of corresponding vector characteristics;
a display device composed of pixels, which takes the lights from the wave-guide backlight unit with time-sequential directional light sources as backlights and each pixel of the display device modulates an incident light beam from the wave-guide backlight unit with time-sequential directional light sources for loading optical image at each time-point;
a wavefront modulation device placed in front of or behind the display device along the propagation directions of the lights from the wave-guide backlight unit with time-sequential directional light sources, which converges the light from each light source to a corresponding viewing zone;
a control device, which sequentially turns on the M light sources at M time-points of each time period with only one light source being turned-on at each time-point, and loads optical information onto each pixel of the display device synchronously, with the loaded optical information of a pixel at a time-point being a projection information of a target scene along a reverse direction of a projection direction corresponding this pixel;
wherein the projection direction corresponding to a pixel at a time-point is a propagation direction of a light beam from this pixel when it enters into the corresponding viewing zone at this time-point, and the three-dimensional display module using optical wave-guide for providing directional backlights is arranged such that totally M different viewing zones get presented.

2. The three-dimensional display module using optical wave-guide for providing directional backlights according to claim 1 , wherein the wavefront modulation device is integrated into the optical wave-guide device.

3. The three-dimensional display module using optical wave-guide for providing directional backlights according to claim 1 , wherein the optical wave-guide device is comprised of an optical wave-guide body, an entrance pupil, a coupling-in device, reflecting surfaces, a coupling-out device and an exit pupil;
wherein, the light from each light source enters the optical wave-guide body through the relay device and the entrance pupil; then, guided by the coupling-in device and reflected by the reflecting surfaces, the light from each light source propagates in the optical wave-guide body toward the coupling-out device; the coupling-out device guides the light from each light source to exit the optical wave-guide body through the exit pupil with corresponding vector characteristics.

4. The three-dimensional display module using optical wave-guide for providing directional backlights according to claim 1 , wherein the M light sources of the wave-guide backlight unit with time-sequential directional light sources are line light sources;
the three-dimensional display module using optical wave-guide for providing directional backlights is arranged such that, for each displayed point, at least two passing-through light beams reach into a pupil positioned around the viewing zones.

5. The three-dimensional display module using optical wave-guide for providing directional backlights according to claim 1 , wherein the M light sources of the wave-guide backlight unit with time-sequential directional light sources are point light sources;
the three-dimensional display module using optical wave-guide for providing directional backlights is arranged such that, for each displayed point, at least one passing-through light beam reaches into a pupil positioned around the viewing zones.

6. The three-dimensional display module using optical wave-guide for providing directional backlights according to claim 1 , wherein a scattering element is attached to the display device for scattering the light beam modulated by a pixel along a one-dimensional direction;
the three-dimensional display module is arranged such that, for each displayed point, at least two passing-through light beams reach into a pupil positioned around the viewing zones.

7. The three-dimensional display module using optical wave-guide for providing directional backlights according to claim 1 , wherein it further comprises a deflection device placed in a propagation path of a light from the wave-guide backlight unit with time-sequential directional light sources for deflecting its propagation direction.

8. The three-dimensional display module using optical wave-guide for providing directional backlights according to claim 1 , wherein it further comprises a compensation unit placed between an external environment and the wavefront modulation device, for eliminating the impact of the wavefront modulation device on optical information from the external environment.

9. The three-dimensional display module using optical wave-guide for providing directional backlights according to claim 1 , wherein the wavefront modulation device is a lens.

10. The three-dimensional display module using optical wave-guide for providing directional backlights according to claim 1 , wherein the wavefront modulation device is a zoom lens with controllable focus;
wherein, the control device is arranged to drive the wavefront modulation device for projecting multiple virtual images of the display device to different depths in a time sequence, and load corresponding information to each pixel of the display device synchronously;
or, according to a viewer's binocular convergence depth detected by an external auxiliary device, the control device is arranged to drive the wavefront modulation device for real-timely projecting the virtual image of the display device to the viewer's binocular convergence depth or a depth near it, and synchronously load corresponding information to each pixel of the display device.

11. The three-dimensional display module using optical wave-guide for providing directional backlights according to claim 10 , wherein the wavefront modulation device is a liquid crystal lens with changeable focal length under the driving of the control device, or a compound liquid crystal lens stacked by more than one liquid crystal plates;
wherein, the compound liquid crystal lens presents different focal lengths through the combination of different liquid crystal plates.

12. The three-dimensional display module using optical wave-guide for providing directional backlights according to claim 1 , wherein it further comprises a light-path-folding structure inserted in the propagation path of the light from the wave-guide backlight unit with time-sequential directional light sources.

13. The three-dimensional display module using optical wave-guide for providing directional backlights according to claim 12 , wherein the light-path-folding structure comprises a first modulation plate, a semi-reflective and semi-transparent plate, a second modulation plate, a selective-reflection/transmission device, wherein the selective-reflection/transmission device reflects a light with one kind of characteristics and transmits a light with another kind of characteristics, which ar

Assignees

• Univ Sun Yat Sen

Inventors

• Liu Lilin
• Teng Dongdong

Classifications

• G02B27/1006 Primary

  for splitting or combining different wavelengths (G02B27/1086, G02B27/141 take precedence) · CPC title

• G02B27/0172 Primary

  characterised by optical features · CPC title

• G02B2027/0178

  Eyeglass type (eyeglass details G02C) · CPC title

• G02B2027/0134

  of stereoscopic type · CPC title

• G02B6/0011

  the light guides being planar or of plate-like form · CPC title